Wireless Sensor Networks for Spectrum Sensing to Support Opportunistic Spectrum Access Networks: Protocol Design and Fundamental Trade-offs

Supporting secondary users through a collateral network dedicated to spectrum sensing has been recently proposed as a mean to overcome spectrum sensing limitations of secondary devices. Building on this idea, we propose a protocol for a Wireless Sensor Network (WSN) to support secondary devices of an Opportunistic Spectrum Access (OSA) network. We examine the fundamental tradeoff between the statistics of the primary network traffic for which the WSN is able to support the OSA network and the interference range or, equivalently, the transmit power of secondary transmitters. We optimize the parameters of the proposed protocol to achieve the minimum delay for delivering channel availability information to secondary users, thus maximizing the portion of time they can effectively use idle primary channels to send their data. We further provide simulation results to demonstrate the feasibility and effectiveness of our design, and point at possible research directions to improve the proposed system capabilities.